This video is about libraries in JavaScript in the Advanced Placement Computer Science Principles AP CSP course. We are looking at the 2024 version of the code.org version of this class. We are in lesson eight or lesson nine of unit seven, make a library. So I'm going to show you exactly how to make a function and how to make it into a library entry. I think one of the functions that is offered is a list function where you just find the average of the numbers in a list.